This invention relates to an apparatus and process for forming a rolled tab in the tail end portion of a plastic film wound on a core. The rolled tab provides a leading edge for a roll of household plastic film in order to provide a convenient grasping tab to start the roll.
Commercial plastic film for consumer use is customarily manufactured by winding plastic film on a core and packaging the roll in a dispensing container for retail sale. The plastic film has a tail end portion extending around the surface of the roll and terminating at a tail edge. The plastic film is customarily manufactured with a clinging or adhesive surface to enhance its function as a wrapping material such as, for example, Saran Wrap.TM. or Handi-Wrap.TM. (trademarks of The Dow Chemical Company) films commonly used as household wrappings. Because of the clinging characteristic of the film, the tail end portion sticks to the surface of the roll making it difficult to identify and grasp the tail edge in order to separate the tail end portion from the surface of the roll without tearing it. The need for finding the tail edge of the film on the roll of plastic film and starting to unwind it without tearing has been long recognized, particularly with plastic film having considerable cling. Hence, roll-starting features have been used in the past to facilitate peeling the tail end portion of the film away from the surface of the roll.
U.S. Pat. Nos. 4,804,513 and 4,925,028, which are incorporated herein by reference, disclose one successful means of providing a rolled tab in a roll of plastic film. The rolled tab, produced by the process and apparatus disclosed in the above patents, helps the consumer find the starting edge of the roll.
The above patents disclose an apparatus adapted for use on a conveyor line to form a rolled tab in the tail end portion of plastic film wound on a roll of plastic film moving on the conveyor line. The tail end portion initially extends circumferentially around the surface of the roll to which the tail end portion adheres and terminates at a tail edge. The apparatus comprises a bucket which is connected to the conveyor line for movement thereon and has a floor and wall extending therefrom. The floor of the bucket has a tractional surface supporting the roll and the wall has a substantially frictionless surface pushing the roll in the direction of the conveyor line. The apparatus further comprises a drive means, extending in a stationary position substantially parallel to the conveyor line and having a resilient tractional surface being compressed into rotational contact with the roll for rotating the roll. The drive means rotates the roll to rub the surface of the roll against the tractional surface of the floor in the same direction that the tail end portion initially extends along the surface of the floor separates the tail end portion from the surface of the roll and rolls the tail edge back on the tail end portion upon successive revolutions of the roll to form a rolled tab containing the tail edge.
U.S. Pat. Nos. 4,804,513 and 4,925,028, also disclose a means, extending in a stationary position substantially parallel to the conveyor line, for blowing air tangentially along the circumferential surface of the roll and against the tail end portion on successive revolutions to assist in separating and rolling the tail end portion of the plastic film.
U.S. Pat. Nos. 4,804,513 and 4,925,028, further disclose a method for forming a rolled tab in the tail end portion of a roll plastic film wound on a core. The roll is propelled along a resilient tractional surface to rotate the roll in the same direction that the tail end portion initially extends along the surface of the roll. The roll is then pressed between the resilient tractional surface and a diametrically opposed moving contact position with a force of sufficient magnitude to compress the resilient tractional surface to form an arc of contact of sufficient length with the roll to maintain traction therebetween. The rotating surface of the roll is then rubbed at the moving contact position while maintaining the traction between the roll and the resilient tractional surface to separate the tail end portion from the surface of the roll and roll the tail edge back on the tail end portion upon successive revolutions of the roll to form a rolled tab containing the tail edge.
The product of the method and apparatus described in U.S. Pat. Nos. 4,804,513 and 4,925,028, is a roll of plastic film which comprises a core and plastic film wound on the core. The plastic film has a clinging surface and a tail end portion on the surface of the roll wherein the tail end portion terminates at a tail edge. The tail edge is rolled back on the tail end portion to form a rolled tab containing the tail edge. As a result, the rolled tab facilitates identifying and grasping the tail edge to initiate use of the roll.
While the apparatus and process described in U.S. Pat. Nos. 4,804,513 and 4,925,028 have experienced success in providing a rolled tab for a roll of plastic film, it is desired to provide an alternative apparatus and method for providing a rolled tab in the roll of plastic film in order to help the consumer find the starting edge of the roll. More particularly, it is desired to provide another apparatus and method which is readily adaptable to existing processing equipment and which can be used with other processing equipment, for example, equipment for applying a coupon in the package of a roll of film.